To study the genetic aspects of fatty acid components in adipose tissues of Syrian Hamsters, a total of ninety animals of three lines were used. One inbred line (GN) was always fed cereals (Diet F) and inbred to the closed herd. Another selected line (ALF) was always fed with alfalfa meal pellet (Diet A) and selected to increase the weaning number. Another control line (GNR) was mated at random, with one of its group always fed cereals without selecting for litter size, and the second group fed an alfalfa pellet. Adipose tissues were taken from three parts of the subcutaneous round of back legs, round of kidney and generative organs. Rates of fatty acid components of total lipids extracted from their tissues were determined by Gas Chromatography and compared statistically to average out random effects of the line, sex, age in weeks, body part and diet. To research for genetic variation of fatty acid components and Δ9-desaturase activity index (Δ9-desat.), genetic parameters of each effect were estimated. ALF seems to increase the animal's productive ability of C18:1, a measure of the efficiency of biosynthesis for mono-unsaturated fatty acids(MUSFA). So, ALF might be introducing a genetic variation by increasing the capacity to make use of energy in reproductive behavior. Estimated heritabilities of MUSFA and Δ9-desat. were 0.73 and 0.61 respectively. Estimated genetic correlation between total saturated fatty acid(SFA) and MUSFA or Δ9-desat. were negative values. Considering the circumstances mentioned above, amounts of fatty acid components in adipose tissues of every part might be induced to genetically. To determine that, it might be useful to use Δ9-desat. as an indicator.